Improvement in beds for polishing plate-glass



R. BROCKMAN.

BEDS FOR POLISHING PLATE-GLASS.

No 178.403'. Patented June 6,1876.

N.PETF.RS. PHOTO-LITHOGRAPHER. WASHINGTON. D c.

UNITED STATES TENT FF 1;;

ROBERT BROCKMAN, OF NEW ALBANY, INDIANA.

IMPROVEMENT IN BEDS FOR POLISHING PLATE-GLASS.

Specification forming part of Letters Patent No. 178,403, dated June 6, 1876 application filed April 4, 1876.

To all whom it may concern:

Be it known that I, ROBERT BROCKMAN, of New Albany, Floyd county, State of Indiana, have invented certain Improvements in Bed- Frames for Polishing Plate-Glass, of which the following is aspecification:

The object of my invention is to provide an improved portable bed-frame for polishing plate-glass, by which breakage of the glass will be prevented, and a better and cleaner finish and a great saving of time and expense will be obtained.

The ordinarily-used bedding for polishing plate-glass is plaster-of-paris, spread out on an iron bench within a frame. In this mass, when in a wet state, the plate or plates of glass are laid. This mode of bedding the glass is expensive, both with regard to the material used and the time it takes to prepare it. With the greatest care hollow spaces are left in the plaster, and as the glass has not the requisite support it is liable to be broken when operated upon. It will be readily understood that the frame and bedding, with the glass plates, cannot be removed from the bench Without injury.

My invention consists in constructing wooden frames, either with solid or with perforated fillings, over which is stretched a suitable textile fabric, resting on the wooden filling and the frame, and held to the sides, so that no folds will form nor displacement of the same be possible.

Accordingly as thicker or thinner glass plates are to be bedded, I employ more or less heavy and soft textile fabric, but I do not confine myself to any certain fabric, as cloth, cotton, canvas, canton-flannel, 850., may be employed. On this soft and even surface I place one or more plates of glass, and hold the same firmly to the sides of the frame or to the interior filling, as the circumstances may be, with aid of clamps and wedges nailed to the wood. bedded, the frames are laid on the commonlyused iron bench and the polishing machinery set in motion. When the polishing is finished,

duplicate glass plates, with the glass thereon,

are in readiness to take their place, and thus the operation of polishing is continued without loss of time.

In order to describe my invention more fully, I refer to-the accompanying drawings, forming a part of this specification.

Figure I is a top view of my improved bedframe for polishing plate-glass, with glass thereon. Fig. II is a bottom view, and Fig. III is a sectional view of the same.

A is the frame. B is the filling of the frame, consisting of the wooden square slats, which cross each other, and are fastened to the inside of the frame A. D is the piece of canvas stretched across the upper side of the filling and the frame. E E are the clamps, and F F are the wedges, with nails gg, which hold the glass plates H H firmly upon the canvas to the frame and bedding.

Having thus described my invention, I desire to claim- A bed-frame for polishing plate-glass when consisting of the frame A, with filling B, and the textilefabric cover D, in combination with the clamps E and wedges F, substantially as described.

ROBERT BROOKMAN.

Witnesses:

J. GIERLoW, H. E. WAGNER.

When the glass plates are thus 

